Je t'en prie

In French, "t'en" is a contraction of "te en," where "te" is the indirect object pronoun meaning "to you," and "en" is a pronoun that can replace a partitive object or an object introduced by "de." 

In "je t'en prie," "te" is combined with "en" to form "t'en." The phrase as a whole translates to "I beg you," but in usage, it serves as a polite response to thanks, similar to "you're welcome" or "don't mention it" in English.

Here's a breakdown:

- "Je" = I

- "te" (contraction to "t'") = to you

- "en" = of it, about it

- "prie" = beg, ask

So, "je t'en prie" literally means "I beg you of it," but is used idiomatically to mean "you're welcome."